Multiple chips or dies may be packaged together in a multi-chip integrated circuit (IC) package. The chips in the IC package may communicate with one another via a digital interface. For example, a radio transceiver chip may communicate with a baseband chip in the IC package via a digital interface. The digital interface may include multiple lines for communicating multiple bits in parallel between chips. However, the digital interface may add complexity to the IC package by requiring multiple lines between chips and/or electrostatic discharge (ESD) protection circuitry. Also, the digital interface may suffer from harmonic interference and/or other types of interference.